This project represents the second phase of a larger research agenda to investigate the development of Prolonged Grief (PG) pathology with an eye toward informing new directions in assessment and clinical intervention. Typically close to 50% of bereaved individuals experience acute grief symptoms in the early months after a loss. Many eventually recover, but a significant subset (10%-15% of all bereaved individuals) continued to suffer from PG reactions that compromise their ability to function for several years and often longer. Extending the previous phase of the research, which was limited to a cross-sectional design, the primary objective of the current project includes a longitudinal design, multiple methods for identifying PG (diagnoses, latent growth mixture modeling), measures of early predictors of the development of PG pathology, and biomarkers (EMG, ERP) of PG-related deficits. The project will assess conjugally bereaved individuals at 4, 14, and 25 months post-loss using structured clinical interviews and a set of experimental and interview tasks. The primary aims are (1) to map diagnoses and longitudinal patterns of PG versus recovery, (2) to assess early deficits in emotion and emotion-related brain activity as predictors of the development of later PG, and (3) to assess emotion regulation and emotion-related brain activity later in bereavement as markers of PG-related deficits. One set of hypotheses predicts that bereaved people with acute grief at 4 months will develop PG at later assessments if they (a) fail to evidence context sensitive emotional responding (e.g., negative emotion in negative topics); (b) generate overall less positive emotion; and (c) exhibit reduced flexibility in modulating both affective experience and emotional expression. A second set of hypotheses predicts that bereaved individuals with PG at 18 months will (a) experience less comfort from representation of the deceased (measured by self-report and facial EMG) and (b) show greater attention toward open-mouth sad faces when primed with spouse-associate words; and (c) express greater nonverbal sadness and less nonverbal positive emotion when describing intimacy with the deceased.